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Diffstat (limited to 'Documentation/media/uapi/v4l/vidioc-query-dv-timings.rst')
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diff --git a/Documentation/media/uapi/v4l/vidioc-query-dv-timings.rst b/Documentation/media/uapi/v4l/vidioc-query-dv-timings.rst deleted file mode 100644 index e9b055395382..000000000000 --- a/Documentation/media/uapi/v4l/vidioc-query-dv-timings.rst +++ /dev/null @@ -1,94 +0,0 @@ -.. Permission is granted to copy, distribute and/or modify this -.. document under the terms of the GNU Free Documentation License, -.. Version 1.1 or any later version published by the Free Software -.. Foundation, with no Invariant Sections, no Front-Cover Texts -.. and no Back-Cover Texts. A copy of the license is included at -.. Documentation/media/uapi/fdl-appendix.rst. -.. -.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections - -.. _VIDIOC_QUERY_DV_TIMINGS: - -***************************** -ioctl VIDIOC_QUERY_DV_TIMINGS -***************************** - -Name -==== - -VIDIOC_QUERY_DV_TIMINGS - VIDIOC_SUBDEV_QUERY_DV_TIMINGS - Sense the DV preset received by the current input - - -Synopsis -======== - -.. c:function:: int ioctl( int fd, VIDIOC_QUERY_DV_TIMINGS, struct v4l2_dv_timings *argp ) - :name: VIDIOC_QUERY_DV_TIMINGS - -.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_QUERY_DV_TIMINGS, struct v4l2_dv_timings *argp ) - :name: VIDIOC_SUBDEV_QUERY_DV_TIMINGS - - -Arguments -========= - -``fd`` - File descriptor returned by :ref:`open() <func-open>`. - -``argp`` - Pointer to struct :c:type:`v4l2_dv_timings`. - - -Description -=========== - -The hardware may be able to detect the current DV timings automatically, -similar to sensing the video standard. To do so, applications call -:ref:`VIDIOC_QUERY_DV_TIMINGS` with a pointer to a struct -:c:type:`v4l2_dv_timings`. Once the hardware detects -the timings, it will fill in the timings structure. - -.. note:: - - Drivers shall *not* switch timings automatically if new - timings are detected. Instead, drivers should send the - ``V4L2_EVENT_SOURCE_CHANGE`` event (if they support this) and expect - that userspace will take action by calling :ref:`VIDIOC_QUERY_DV_TIMINGS`. - The reason is that new timings usually mean different buffer sizes as - well, and you cannot change buffer sizes on the fly. In general, - applications that receive the Source Change event will have to call - :ref:`VIDIOC_QUERY_DV_TIMINGS`, and if the detected timings are valid they - will have to stop streaming, set the new timings, allocate new buffers - and start streaming again. - -If the timings could not be detected because there was no signal, then -ENOLINK is returned. If a signal was detected, but it was unstable and -the receiver could not lock to the signal, then ``ENOLCK`` is returned. If -the receiver could lock to the signal, but the format is unsupported -(e.g. because the pixelclock is out of range of the hardware -capabilities), then the driver fills in whatever timings it could find -and returns ``ERANGE``. In that case the application can call -:ref:`VIDIOC_DV_TIMINGS_CAP` to compare the -found timings with the hardware's capabilities in order to give more -precise feedback to the user. - - -Return Value -============ - -On success 0 is returned, on error -1 and the ``errno`` variable is set -appropriately. The generic error codes are described at the -:ref:`Generic Error Codes <gen-errors>` chapter. - -ENODATA - Digital video timings are not supported for this input or output. - -ENOLINK - No timings could be detected because no signal was found. - -ENOLCK - The signal was unstable and the hardware could not lock on to it. - -ERANGE - Timings were found, but they are out of range of the hardware - capabilities. |